1. [Field of the Invention]
The present invention relates to a semiconductor device and a method for fabricating the same, and particularly to a semiconductor device including a MOS (metal oxide semiconductor) transistor and a method for fabricating the same.
2. [Description of the Related Art]
FIG. 6A to FIG. 6C show a method for fabricating a MOS transistor in a prior art.
As shown in FIG. 6A, silicon oxide films 607 having a predetermined pattern are formed on a silicon region 601. A source region 602 and a drain region 603 are formed on a surface of the silicon region 601. A gate oxide film 604 is formed on a channel region between the source region 602 and the drain region 603. On the gate oxide film 604, a gate electrode 605 and sidewalls (silicon oxide) 606 are formed.
Next, as shown in FIG. 6B, a titanium layer 611 is formed on a substrate. Predetermined annealing is then performed so that silicide (TiSi2) is formed at an interface between the source region 602 and the titanium layer 611, an interface between the gate electrode 605 and the titanium layer 611, and an interface between the drain region 603 and the titanium layer 611.
Subsequently, the titanium layer 611 is etched. As shown in FIG. 6C, the titanium layer 611 is removed and silicide 631, 632, and 633 at respective interfaces remain.
The MOS transistor is formed on an SOI (silicon on insulator) substrate so that the operation of the MOS transistor can be speeded up. However, the formation of the silicide on the gate electrode sometimes causes the reduction in operation speed of a the MOS transistor.